The aforementioned application Ser. No. 410,070 provides heat to the hydropyrolysis of a hydrocarbonaceous fuel such as a bituminous coal or a heavy residual oil. The hydropyrolysis is conducted in a slow, stationary fluidized bed of coke pellets with accretion of the coke product of the hydropyrolysis upon the pellets. Heat is provided by circulating a hot fine solid into a fast fluidized bed of this solid that is superposed above the slow fluidized bed of coke pellets and therefore is in thermal communication therewith. The residence time of vapor product is limited to preserve benzene product along with methane product of the hydropyrolysis.
The application Ser. No. 410,070 also discloses an arrangement for gasifying the coke pellets, for which several other aspects are disclosed in the aforementioned co-pending application Ser. No. 257,432, to issue as U.S. Pat. No. 3,840,353, and in the two aforementioned co-pending applications filed simultaneously herewith. In the arrangement, larger particles of coke arising from a coal or coke feedstock form a slow, stationary fluidized bed zone. Finer particles of coke arise from finer particles in the feedstock or from the degradation of the larger coke particles of the slow bed zone as these particles waste away in the course of the gasification process. The finer particles form a superposed fast fluidized bed zone contiguous with the slow bed zone and therefore in thermal communication therewith. Oxygen reacts exothermically with carbon in the lower zone to provide endothermic heat for the reaction of carbon with steam or carbon dioxide in both zones. Endothermic heat for the reaction in the upper zone passes from the lower slow bed zone to the upper fast bed zone by thermal conduction. When coals are gasified or cokes produced from coals, and with use of a temperature in the fluidized bed zones between about 1,900.degree. F. and about 2,650.degree. F., the arrangement provides a way to withdraw ash matter in form of ash agglomerates of low carbon content that form and grow in the slow bed zone and remain freely fluidized along with the coke in this zone until they are withdrawn from the bottom of the slow bed zone.